As AI assistants learn an individual's preferences, style, and context, their utility becomes deeply personalized. This creates a powerful lock-in effect, making users reluctant to switch to competing platforms, even if those platforms are technically superior.

Businesses become critically dependent on platforms for even a small fraction of their revenue (e.g., 20%). This 'monopsony power' creates a stronger lock-in than user network effects, as losing that customer base can bankrupt the business.

For subscription services, the most effective moat isn't the software itself, which can be replicated, but the accumulated user data. Users are reluctant to switch apps because they would lose years of personal history, stats, and community connections, creating strong lock-in.

Substack's new policy requiring readers to install its app to finish articles is a major strategic pivot. It moves the company away from its founding ethos of direct, unmediated creator-audience relationships via email and towards building a walled-garden social network, potentially at the expense of its creators.

Substack is more of a social network with email features than a robust email service provider (ESP). The optimal strategy is to leverage its discovery features, like Notes, to acquire subscribers, then regularly export those emails to a primary ESP where you fully control the audience relationship.

X doesn't need to convince top writers to abandon platforms like Substack. Their goal is to get those writers to cross-post free content onto X, thereby capturing valuable long-form text and user attention without needing to replicate Substack's entire creator-friendly ecosystem.

Making user data and audiences portable seems counterintuitive to retention. However, Substack found that by allowing creators to export their email lists, it removed the fear of platform lock-in. This trust makes creators more willing to invest deeply in the platform.

Avoid building your primary content presence on platforms like Medium or Quora. These platforms inevitably shift focus from serving users to serving advertisers and their own bottom line, ultimately degrading reach and control for creators. Use them as spokes, but always own your central content hub.

Despite ChatGPT building features like Memory and Custom Instructions to create lock-in, users are switching to competitors like Gemini and not missing them. This suggests the consumer AI market is more fragile and less of a winner-take-all monopoly than previously believed, as switching costs are currently very low.